This self-study module is part of the series ‘Introduction to Plant Biology’ and focuses on the role of water in plants, explaining how water is taken up, transported, and regulated to support plant growth and survival. It is designed for students learning basic plant biology and for teachers seeking clear figures and explanations for educational use. The module covers water uptake by roots, long-distance water transport through the xylem and phloem, the relationship between stomata and transpiration, and examines how environmental factors influence these processes.